Excellent product, it consumes only 7 watts without load with the display lamp on, quite less than my others autotransfo (but not important as it's a laboratory device).the digital display lacks of precision at low voltage (give 20V when in fact 25V). The lack of accuracy is never over 5V of error, however, it becomes acurate around 200V. with an input at 220v it goes up to 310volt. The device is humming a bit as it is powerfull (1000 VA).